The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Aug. 31, 1999
Filed:
May. 29, 1997
Kiyoko Takeda, Amagasaki, JP;
Shigeki Azuma, Nishinomiya, JP;
Yoshio Tarutani, Sanda, JP;
Yoshitaka Nishiyama, Nishinomiya, JP;
Yasushi Matsuda, Amagasaki, JP;
Sumitomo Metal Industries, Ltd., Osaka, JP;
Abstract
A stainless steel having excellent corrosion resistance to ozone added water, such as ozone added ultrapure water used in semiconductor manufacturing processes and the like, as well as a manufacturing method. The stainless steel comprises a base metal and an oxide film formed on the surface of the base metal, the base metal being a stainless steel which contains 12 to 30% of Cr, 0 to 35% of Ni, and 1 to 6% of Al and Si while the contents of the other alloying elements are limited to as low a level as possible, the oxide film mainly comprising Al oxide or a Si oxide or both. The oxide film may be formed on the base metal surface through the dry oxidation process or the wet oxidation process. In the stainless steel, metallic ions are rarely dissolved from the base metal into the ozone added water. Also, since the contents of alloying elements, other than Cr, Ni, Al, Si, and like necessary elements, are limited to a low level, the stainless steel exhibits excellent corrosion resistance and reduced particle emission.